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Caillault, Nathalie. "Systeme cuo-bi#2o#3-sb#2o#3 structures et proprietes electriques des ceramiques de type pyrochlore m#i#im#1#,#5#i#i#im#1#,#5#vo#7 (m#i#i=cu, zn, cd; m#i#i#i=bi, y, gd; m#v=sb, nb)." Limoges, 1990. http://www.theses.fr/1990LIMO0096.
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L'etude du systeme cuo-bi#2o#3-sb#2o#5 a permis de mettre en evidence, outre quatre composes definis deja signales: bisbo#4, bi#3sbo#7, cusb#2o#6 et cubi#2o#4, un compose defini cu#4sb#2o#9 bixbyite et deux phases non-stchiometriques bi#1#-#xcu#xo#1#,#5#-#x#/#2 sillenite et cu#2#-#2#xbi#3#xsb#2#-#xo#7 pyrochlore. Les substitutions cationiques (la, y, gd-bi; nb-sb) realisees sur la phase prototype mb#1#,#5sb#1#,#5o#7 (m=cu, zn, cd) ont permis d'etudier l'influence des differents cations sur les proprietes cristallochimiques et les proprietes electriques qui en resultent
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Costa, Maria Jos? Fonseca. "S?ntese e caracteriza??o de materiais nanoporosos para pir?lise catal?tica de ?leos pesados." Universidade Federal do Rio Grande do Norte, 2008. http://repositorio.ufrn.br:8080/jspui/handle/123456789/17609.
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Previous issue date: 2008-12-22Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
The present work reports the study of nanoporous structures, aiming at their use in research directed to the current demand of the petroleum industry to value heavy oil. Initially, two ways were chosen for the synthesis of porous structures from the molecular sieves of type Si-MCM-41. In the first way, the structure MCM-41 is precursory for heteroatom substitutes of silicon, generating catalyst of the type Al-MCM-41 from two different methods of incorporation of the metal. This variation of the incorporation method of Aluminum in the structure of Si-MCM-41 was carried out through the conventional procedure, where the aluminum source was incorporated to the gel of synthesis, and the procedure post-synthesis, where the Aluminum source was incorporated in catalyst after the synthesis of Si-MCM-41. In the second way, the MCM-41 acts as a support for growth of nanocrystals of zeolite embedded in their mesoporous, resulting in hybrid MCM-41/ZSM-5 catalyst. A comparative analysis was carried through characterizations by XRD, FTIR, measures of acidity through n-butylamine adsorption for TGA, SEM-XRF and N2 adsorption. Also crystalline aluminosilicate with zeolitic structure MFI of type ZSM-5 was synthesized without using organic templates. Methodologies to the preparation of these materials are related by literature using conventionally reactants that supply oxides of necessary silicon and aluminum, as well as a template agent, and in some cases co-template. The search for new routes of preparation for the ZSM-5 aimed at, above all, the optimization of the same as for the time and the temperature of synthesis, and mainly the elimination of the use of organic templates, that are material of high cost and generally very toxic. The current study is based on the use of the H2O and Na+ cations playing the role of structural template and charge compensation in the structure. Characterizations by XRD, FTIR, SEM-XRF and N2 adsorption were also conducted for this material in order to compare the samples of ZSM-5 synthesized in the absence of template and those used industrially and synthesized using structuring
O presente trabalho relata o estudo de estruturas nanoporosas, visando o uso em pesquisas que atendam a atual demanda da ind?stria do petr?leo, de valorizar ?leos pesados. Inicialmente, optou-se por duas vertentes para a s?ntese de estruturas porosas a partir da peneira molecular do tipo Si-MCM-41. Na primeira vertente, a estrutura MCM-41 ? precursora para hetero?tomos substituintes do sil?cio, gerando catalisadores do tipo Al-MCM-41 a partir de dois diferentes m?todos de incorpora??o do metal. Essa varia??o do m?todo de incorpora??o do Alum?nio na estrutura do Si-MCM-41 se deu atrav?s do procedimento convencional, no qual a fonte de alum?nio foi incorporada ao gel de s?ntese e do procedimento p?s-s?ntese, no qual a fonte de Alum?nio foi incorporada ao catalisador ap?s a s?ntese do Si-MCM-41. Na segunda vertente, o MCM-41 age como suporte para o crescimento de nanocristais de ze?lita embutidos nos seus mesoporos, resultando no catalisador h?brido MCM-41/ZSM-5. Uma an?lise comparativa foi realizada atrav?s de caracteriza??es por XRD, FTIR, medidas de acidez atrav?s de dessor??o de n-butilamina por TGA, SEM-XRF e Adsor??o de N2. Tamb?m foi sintetizado um aluminossilicato cristalino com estrutura zeol?tica MFI do tipo ZSM-5, na aus?ncia total de direcionador org?nico. Metodologias relacionadas ? prepara??o desses materiais s?o relatadas pela literatura utilizando-se convencionalmente reagentes que forne?am os ?xidos de sil?cio e de alum?nio necess?rios, bem como um agente direcionador, e em alguns casos at? co-direcionadores. A busca por novas rotas de prepara??o para a ZSM-5 visou, sobretudo, a otimiza??o da mesma no que se refere ao tempo e ? temperatura de s?ntese, e principalmente a elimina??o do uso dos direcionadores org?nicos, que s?o materiais de alto custo e geralmente muito t?xicos. O atual estudo se baseia na utiliza??o da H2O e dos c?tions Na+ desempenhando o papel de direcionamento estrutural e compensa??o de cargas na estrutura. Caracteriza??es por XRD, FTIR, SEM-XRF e Adsor??o de N2 tamb?m foram realizadas para esse material, a fim de comparar as amostras de ZSM-5 sintetizadas na aus?ncia do direcionador e aquelas utilizadas industrialmente e sintetizadas utilizando estruturantes
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Nganga, Léon. "Contribution à l'étude du matériau supraconducteur à température critique élevée YBa2Cu3O7: cristallogénèse et caractérisations physico-chimiques." Phd thesis, Université Sciences et Technologies - Bordeaux I, 1990. http://tel.archives-ouvertes.fr/tel-00173106.
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Des monocristaux de YBa2Cu3O7 ont été préparés par une méhode de flux en creuset d'or. Une analyse des spirales de croissance et des domaines ferroélastiques révélés par une étude en microscopie optique en lumière polarisée et en microscopie électronique a balayage sur la face principale (001) à été effectuée. Un ensemble de caractérisations physico-chimiques (diffraction X, EPMA, détermination de la température critique par mesures électriques, spectroscopie micro-Raman, mesures des susceptibilités alternatives en champ faible) réalisé sur des cristaux bruts de croissance et recuits sous oxygène à permis de relier l'évolution des propriétés supraconductrices à la non stoechiométrie en oxygène. Enfin le phénomène de dégradation atmosphérique de YBa2Cu3O7 à été confirmé par une étude sur monocristal, à l'aide des techniques spectroscopiques (micro-Raman, Auger, XPS)
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CASTRO, Aleff Cruz de. "SENSOR ELETROQUÍMICO À BASE DE NiAlPO-5 PARA DETERMINAÇÃO DE Cu2+ EM ETANOL COMBUSTÍVEL." Universidade Federal do Maranhão, 2017. http://tedebc.ufma.br:8080/jspui/handle/tede/1242.
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CNPq, FAPEMA, CAPES, FSADU
Zeolites are microporous inorganic materials with a variety of applications in several areas of science and engineering. Their physical and chemical properties are attributed to the large internal surface area, and the chemical and hydrothermal stability, which are induced by the existence of well defined channels and/or cavities. These structural characteristics promote the use of zeolites as catalysts, molecular sieves, ion exchangers and, more recently, as electrochemical sensors. Taking in consideration these premises, this work describes the development of an electrochemical sensor obtained from the modification of the polyurethane graphite composite electrode with NiAlPO-5, a nickel-modified AFI aluminophosphate, and its application for determination of Cu2+ in ethanol biofuel. The synthesis of the aluminophosphates were conducted by the hydrothermal method and the obtained materials were characterized by X-ray diffraction, scanning electron microscopy, 31P nuclear magnetic resonance and UV-Vis and infrared spectroscopy. After synthesis and characterization, materials were used as modifiers (10%) in GPU electrodes in order to compare the performance of the unmodified and modified electrodes by Square Wave Anodic Stripping Voltammetry. The results showed that the incorporation of Ni to the material structure promotes an improvement in the electrical properties and analytical properties of the electrode. The analytical response of the sensor in the copper ion determination showed that the NiAlPO-5 electrode is more sensitive in terms of peak current than the electrolyte based on AlPO-5 only. The best response was obtained with the Ni/Al ratio of 0.5 on the NiAlPO-5 sensor. The experimental conditions of potential and deposition time, pulse amplitude, step potential, frequency and pH were optimized in an electrochemical cell containing 2 mL of ethanol, 8 mL of HCl 0.1 mol L-1 and Cu2+ concentration of 2.5×10-7 mol L-1. GPU/NiAlPO-5 modified sensor was then evaluated for electroanalytical determination of Cu2+ in ethanol biofuel samples presenting a linear response for Cu2+. Good results were obtained for the limit of detection (9.44×10-9 mol L-1), accuracy (recovery of 115%) and precision (RSD of 5.92%).
As zeólitas são materiais inorgânicos microporosos que apresentam uma grande variedade de aplicações em diversas áreas das ciências e engenharias. Suas propriedades físicas e químicas são atribuídas à grande área superficial interna e à estabilidade química e hidrotérmica, as quais são induzidas pela existência de canais e/ou cavidades bem definidos, tornando possível a sua utilização como catalisadores, peneiras moleculares, trocadores iônicos e, mais recentemente, como sensores eletroquímicos. Com base nisto, este trabalho apresenta o desenvolvimento de um sensor eletroquímico obtido a partir da modificação do eletrodo compósito de grafite poliuretana com NiAlPO-5, um aluminofosfato de estrutura AFI modificado com níquel, e sua aplicação na determinação de Cu2+ em amostras de etanol combustível. Os aluminofosfatos foram sintetizados através do método hidrotérmico e caracterizados por difração de raios-X, microscopia eletrônica de varredura, ressonância magnética nuclear de 31P e espectroscopia de UV-Vis e de infravermelho. Os materiais obtidos foram, então, utilizados como modificadores na proporção de 10% em eletrodos GPU, a fim de realizar-se uma comparação entre os eletrodos sem modificação e modificados com AlPO-5 e NiAlPO-5 mediante a utilização da técnica de voltametria de redissolução anódica com varredura de onda quadrada e o método de adição padrão. Os resultados mostraram que a incorporação do Ni à estrutura do material promove uma melhora nas propriedades elétricas e analíticas do eletrodo. A resposta analítica do sensor na determinação do íon Cu2+, mostrou que o eletrodo NiAlPO-5 é mais sensível, em termos de corrente de pico, que o eletrodo baseado apenas em AlPO-5. A melhor resposta foi obtida com a razão Ni/Al de 0,5 no sensor NiAlPO-5. As condições experimentais, potencial e tempo de deposição, amplitude de pulso, potencial de escada, frequência e pH foram otimizadas em uma célula eletroquímica contendo 2 mL de etanol, 8 mL de HCl 0,1 mol L-1 e uma concentração de Cu2+ de 2,5×10-7 mol L-1. O sensor modificado com NiAlPO-5 foi então avaliado para determinação eletroanalítica de Cu2+ em amostras de etanol combustível apresentando resposta linear para Cu2+. Bons resultados foram obtidos para o limite de detecção (9,44×10-9 mol L-1), limite de quantificação (3,15 x10-8 mol L-1), recuperação (115%) e precisão (5,92%).
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Fernandes, Juliana Esteves. "Catalisadores Cu-, Co- ou Fe-ZSM-5 caracterização e avaliação na redução de NO a N2 com hidrocarbonetos na presença ou ausência de vapor de água." Universidade Federal de São Carlos, 2005. https://repositorio.ufscar.br/handle/ufscar/4146.
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Previous issue date: 2005-03-04Universidade Federal de Sao Carlos
The minimization of the emissions of nitrogen oxides (NOx) in the atmosphere has been one of the great goals in the area of environmental protection. Among the possible processes to treat the NOx, the selective catalytic reduction of NO with hydrocarbons (SCR-HC) has presented important expectations. For this process, the metal/ZSM-5 type catalysts have appropriate levels of conversion in oxidative conditions. In this context, the aim of this work was to prepare Cu, Co and FeZSM-5 catalysts. The samples were characterized by XRD, DRS-UVVIS, FTIR, H2-TPR, SEM and tested in the reduction of NO to N2 with propane or methane in oxidative atmosphere in the presence or absence of water steam. The H2-TPR data showed that the cationic species present in the prepared Cu, Co and FeZSM-5 catalysts, after thermal activation, were mainly Cu2+ (Cuα 2+ e Cuβ 2+), Co2+ and Fe3+ cations located in charge compensation sites in the zeolite, respectively. From FTIR and DRS-UVVIS it was also possible identify oxide species, which were present in a lower content. In the reduction of NO to N2 in the absence of water steam, the CuZSM-5 catalysts showed higher levels of conversion of NO than those based in Co and Fe. However, the FeZSM-5 catalysts showed, in this condition, activity at lower temperatures. This behavior makes them potentially interesting to be applied for practical purposes. On the other hand, in the presence of water steam, it was verified a higher loss of activity of the CuZSM-5 catalyst, which was totally restored removing the water in the feed. For the Co and FeZSM-5 catalysts, the activity loss in the presence of water steam was partially recovered during time on stream.
A minimização das emissões de óxidos de nitrogênio (NOx) na atmosfera tem sido um dos grandes desafios da área de proteção ambiental. Dentre os processos para o tratamento dos NOx possíveis, a redução catalítica seletiva do NO com hidrocarbonetos (RCS-HC) vem apresentando excelentes perspectivas. Para este processo os catalisadores metal/zeólita ZSM-5 possuem adequados níveis de conversão em condições oxidantes. Dentro deste contexto, este trabalho teve como objetivo preparar catalisadores Cu, Co e FeZSM-5. As amostras foram caracterizadas por DRX, DRS-UVVIS, FTIR, RTP-H2, MEV e sua atividade verificada através da redução de NO a N2 com propano ou metano em atmosfera oxidante, na presença ou ausência de vapor de água. Os resultados de RTP-H2 mostraram que as espécies presentes nos catalisadores Cu, Co e FeZSM-5, após ativação térmica, foram principalmente os cátions Cu2+ (Cuα 2+ e Cuβ 2+), Co2+ e Fe3+ compensando carga na zeólita, respectivamente. A partir de FTIR e DRS-UVVIS foi possível, também, identificar espécies oxidas, as quais estavam presentes em teores menores. Na redução de NO a N2 na ausência de vapor de água os catalisadores CuZSM-5 apresentaram maiores conversões de NO que os contendo Fe ou Co. Entretanto, os catalisadores FeZSM-5 apresentaram, nessa condição, atividade em temperaturas menores, o que mostra uma vantagem para o seu uso prático. Na presença de vapor de água, verificou-se uma maior queda da atividade no catalisador CuZSM-5, somente recuperada com a retirada desse composto na alimentação, sendo que para os catalisadores CoZSM-5 e FeZSM-5 a perda de atividade foi parcialmente recuperada ao longo do tempo.
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Lucena, Flávia Raquel Santos. "Avaliação da toxicidade, atividade antitumoral de 5-fluorouracil incorporado a redes de coordenação multifuncionais." Universidade Federal de Pernambuco, 2013. https://repositorio.ufpe.br/handle/123456789/13373.
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Relatos na literatura vêm utilizando nanoparticulas com o objetivo de carrear drogas e diminuir seus efeitos colaterais. Dentro dessa perspectiva estão às redes coordenadas a metais orgânicos ou MOFs. Este trabalho teve como objetivo realizar a incorporação de um fármaco antitumoral em uma rede de coordenação, visando melhorar sua biodisponibilidade para o organismo, bem como avaliar a toxicidade deste sistema in vitro e in vivo. Para isso foi realizado estudo teórico-computacional que nos permitiu a escolher o melhor fármaco a ser utilizado (5-fluorouracil) e a melhor rede de coordenação (Cu-BTC MOF), levando em consideração os tamanhos das moléculas dos mesmos em relação ao tamanho dos poros das MOFs Cu-BTC e MIL-53(Al). Os resultados das caracterizações químicas realizadas (UV-VIS, IV, CNHS, DRX, TGA/DTG e DSC) indicaram uma incorporação de 0,82 g de 5-fluorouracil para cada 1 g de MOF Cu-BTC após sete dias de agitação. A cultura celular in vitro demonstrou que o sistema 5-FU + Cu-BTC MOF apresentou atividade citotóxica significante quando comparado ao fármaco em solução. O teste de verificação do mecanismo de morte celular utilizando a citometria de fluxo indicou ser a apoptose o mecanismo de ação responsável para eliminação das células tumorais. O estudo de dissolução indicou uma liberação lenta e controlada de 39% do fármaco nos primeiros 30 minutos seguida da liberação de 82% do fármaco em 48 horas. Alterações histológicas só foram evidenciadas quando utilizada a dose de 750mg/kg sendo esta, a dose letal (DL50) encontrada. O teste da peritonite, verificação dos níveis de citocinas pro-inflamatórias e produção de óxido demonstraram que o sistema 5-FU + Cu-BTC MOF reduziu o número de leucócitos, os níveis de citocinas pró-inflamatórias e óxido nítrico, indicando que o sistema apresentou também atividade antiinflamatória para os testes realizados. Os resultados indicaram ser o sistema 5-FU+Cu-BTC MOF um excelente carreador de fármaco, com indicação de atividade anti-inflamatória, excelente atividade citotóxica via mecanismo de apoptose e liberação lenta e gradual do fármaco, o que possibilitou a diminuição na toxicidade do mesmo acompanhado de uma significante melhora terapêutica.
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Campbell, Erin, and Hanna Fares. "Roles of CUP-5, the Caenorhabditis elegans orthologue of human TRPML1, in lysosome and gut granule biogenesis." BioMed Central, 2010. http://hdl.handle.net/10150/610355.
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BACKGROUND:CUP-5 is a Transient Receptor Potential protein in C. elegans that is the orthologue of mammalian TRPML1. Loss of TRPML1 results in the lysosomal storage disorder Mucolipidosis type IV. Loss of CUP-5 results in embryonic lethality and the accumulation of enlarged yolk granules in developing intestinal cells. The embryonic lethality of cup-5 mutants is rescued by mutations in mrp-4, which is required for gut granule differentiation. Gut granules are intestine-specific lysosome-related organelles that accumulate birefringent material. This link between CUP-5 and gut granules led us to determine the roles of CUP-5 in lysosome and gut granule biogenesis in developing intestinal cells.RESULTS:We show that CUP-5 protein localizes to lysosomes, but not to gut granules, in developing intestinal cells. Loss of CUP-5 results in defects in endo-lysosomal transport in developing intestinal cells of C. elegans embryos. This ultimately leads to the appearance of enlarged terminal vacuoles that show defective lysosomal degradation and that have lysosomal and endosomal markers. In contrast, gut granule biogenesis is normal in the absence of CUP-5. Furthermore, loss of CUP-5 does not result in inappropriate fusion or mixing of content between lysosomes and gut granules.CONCLUSIONS:Using an in vivo model of MLIV, we show that there is a defect in lysosomal transport/biogenesis that is earlier than the presumed function of TRPML1 in terminal lysosomes. Our results indicate that CUP-5 is required for the biogenesis of lysosomes but not of gut granules. Thus, cellular phenotypes in Mucolipidosis type IV are likely not due to defects in lysosome-related organelle biogenesis, but due to progressive defects in lysosomal transport that lead to severe lysosomal dysfunction.
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Zheng, Quanxing. "Conversion of 2,3-butanediol over bifunctional catalysts." Diss., Kansas State University, 2016. http://hdl.handle.net/2097/34461.
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Doctor of PhilosophyDepartment of Chemical Engineering
Keith L. Hohn
In this study, Cu/ZSM-5 catalysts were used to catalyze the hydrodeoxygenation of 2,3-butanediol to butenes in a single reactor in the presence of hydrogen. The carbon selectivity of butenes increased with increasing SiO₂/Al₂O₃ ratio (lowering acidity of zeolite) and H₂/2,3-butanediol ratio. Cu/ZSM-5 with a SiO₂/Al₂O₃ ratio of 280 showed the best activity toward the production of butenes. On zeolite ZSM-5(280), the carbon selectivity of butenes increased with increasing copper loading and 19.2wt% of CuO showed the highest selectivity of butenes (maximum 71%). The optimal reaction temperature is around 250 °C. Experiments demonstrated that methyl ethyl ketone (MEK) and 2-methylpropanal are the intermediates in the conversion of 2,3-butanediol to butenes. The optimal performance toward the production of butene is the result of a balance between copper and acid catalytic functions. Due to the functionalized nature of 2,3-butanediol, a variety of reactions can occur during the conversion of 2,3-butanediol, especially when multiple catalyst functionalities are present. To investigate the role of the metal (Cu) and acid sites in the process of reaction, the reaction kinetics for all major intermediate products (acetoin, MEK, 2-methylpropanal, 2-butanol and 2-methyl-1-propanol) were measured over Cu/ZSM-5(280), HZSM-5(280), and Cu/SiO₂ at 250 °C. The results showed that Cu is the active site for hydrogenation reactions, while the acidic sites on the zeolite are active for dehydration reactions. In addition, dehydration of alcohols over the zeolite is much faster than hydrogenation of ketone (MEK) and aldehyde (2-methylpropanal). A kinetic model employing Langmuir-Hinshelwood kinetics was constructed in order to predict 2,3-butanediol chemistry over Cu/ZSM-5(280). The goal of this model was to predict the trends for all species involved in the reactions. Reactions were assumed to occur on two sites (acid and metal sites) with competitive adsorption between all species on those sites. Two different types of mesoporous materials (Al-MCM-48, Al-SBA-15) and hierarchical zeolite (meso-ZSM-5) were loaded with ~20wt% CuO and investigated in the conversion of 2,3-butanediol to butenes. The results showed that the existence of mesopores on the catalysts (Al-MCM-48 and Al-SBA-15 types) could decrease the selectivities of products from cracking reactions, especially C₃= and C₅=−C₇= by comparison with the catalyst with ~20wt% CuO loaded on the regular HZSM-5(280); meanwhile, the selectivity of C₈= from oligomerization of butenes was found to increase with increasing pore size of the catalysts. With respect to Cu/meso-ZSM-5(280) catalyst, it can be seen that the catalyst performs in a similar way to both Cu/ZSM-5(280) catalyst and mesoporous copper catalysts (Cu/Al-MCM-48 and Cu/Al-SBA-15) since both micropores (diameter of ~0.55 nm) and mesopores (pore size of ~23 nm) exist on meso-ZSM-5(280). The results from Cu catalysts were compared with four other metal catalysts (Ni, Pd, Rh and Pt). It was found that Cu is not very active for hydrogenation of butenes, but is active for hydrogenation of carbonyl groups (C=O) to form hydroxyl groups (−OH). Pd, on the other hand, is active in further hydrogenating butenes and other unsaturated hydrocarbons. Both Ni and Rh catalysts are good for hydrogenation of olefins and cracking of heavy hydrocarbons; however, Rh is not as good as Ni for the hydrogenation of the carbonyl group (C=O) of MEK. In addition, Pt favors the formation of heavy aromatics such as 5-ethyl-1,2,3,4-tetrahydro-naphthalene, while Pd is active for the production of xylene.
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Huynh, Julie. "ESCRT-Dependent Cell Death in a Caenorhabditis elegans Model of the Lysosomal Storage Disorder Mucolipidosis Type IV." Thesis, The University of Arizona, 2015. http://hdl.handle.net/10150/595811.
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Mutations in MCOLN1, which encodes the cation channel protein TRPML1, result in the neurodegenerative lysosomal storage disorder Mucolipidosis type IV. Mucolipidosis type IV patients show lysosomal dysfunction in many tissues and neuronal cell death. The orthologue of TRPML1 in Caenorhabditis elegans is CUP-5; loss of CUP-5 results in lysosomal dysfunction in many tissues and death of developing intestinal cells that results in embryonic lethality. We previously showed that a null mutation in the ATP-Binding Cassette transporter MRP-4 rescues the lysosomal defect and embryonic lethality of cup-5(null) worms. Here we show that reducing levels of the Endosomal Sorting Complex Required for Transport (ESCRT)-associated proteins DID-2, PHI-33, and ALX-1/EGO-2, which mediate the final de-ubiquitination step of integral membrane proteins being sequestered into late endosomes, also almost fully suppress cup-5(null) mutant lysosomal defects and embryonic lethality. Indeed, we show that MRP-4 protein is hypo-ubiquitinated in the absence of CUP-5 and that reducing levels of ESCRT-associated proteins suppresses this hypo-ubiquitination. Thus, increased ESCRT-associated de-ubiquitinating activity mediates the lysosomal defects and corresponding cell death phenotypes in the absence of CUP-5.
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Bisacchi, Lorenzo. "Elettroriduzione selettiva del 5-idrossimetilfurfurale: studio dei parametri di reazione." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/19231/.
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I processi di riduzione del 5-idrossimetilfurfurale (HMF) sono generalmente condotti mediante processi che utilizzano calore e alte pressioni di H2. Una via alternativa prevede l’applicazione di processi elettrochimici, i quali richiedono condizioni più blande e non necessitano di H2.
Il lavoro di tesi qui presentato si concentra sullo studio della elettoriduzione del 5-idrossimetilfurfurale a 2,5-bis(idrossimetil)furano, tramite l’utilizzo di catalizzatori basati su schiume 3D a cella aperta di Cu, sopra le quali viene depositato Ag tramite elettrodeposizione. La caratterizzazione elettrochimica è stata condotta tramite voltammetrie a scansione lineare fatte in tampone borato 0,5M e in HMF, seguite da cronoamperometrie (CA) e cronopotenziometrie (CP); inoltre sono stati valutati l’effetto dei parametri di reazione, quali concentrazione iniziale di reagente, potenziale applicato e densità di corrente applicata sulla conversione, selettività ed efficienza faradica. Le prove effettuate a due diverse concentrazioni di HMF (0,02M e 0,05M), con potenziale di -1,3V vs SCE, mostrano che all’aumentare della concentrazione di reagente si ha un calo della selettività in BHMF. Mantenendo la concentrazione a 0,05M e variando il potenziale applicato, si è osservato un aumento importante della selettività in BHMF a potenziali meno catodici e un calo della conversione a potenziali più catodici; la prova a -1,25V vs SCE fornisce i migliori risultati, tuttavia il tempo di reazione a questo potenziale è molto elevato, portando ad un netto calo della produttività. All’aumentare della densità di corrente si osserva un aumento della selettività in BHMF e una riduzione della conversione, mentre la FE è stabile.
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Ziegler, Fabian. "Investigation of the Structure and Dynamics of Multiferroic Systems by Inelastic Neutron Scattering and Complementary Methods." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2018. http://hdl.handle.net/11858/00-1735-0000-002E-E5A6-5.
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Mantovani, Luca. "Studio del metodo di preparazione di elettrocatalizzatori 3D Ag/Cu nella riduzione selettiva del 5-idrossimetilfurfurale." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/16674/.
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In questo lavoro di tesi sono stati preparati elettrocatalizzatori metallici 3D di argento supportato su schiume di rame a cella aperta, impiegandoli nella riduzione selettiva del 5-idrossimetilfurfurale (HMF) a 2,5-bisidrossimetilfurano (BHMF). L’utilizzo di questi supporti consente di incrementare l’area superficiale a disposizione, rispetto ai supporti 2D. La preparazione delle schiume è stata effettuata utilizzando due metodi di deposizione: spostamento galvanico ed elettrodeposizione. Lo scopo del lavoro è valutare l’influenza del metodo di deposizione sull’attività catalitica, per questo motivo le schiume bimetalliche ottenute sono state confrontate a quelle monometalliche di rame e argento. Inoltre è stato studiato l’effetto della concentrazione di HMF sulle prestazioni dei catalizzatori, con l’obiettivo finale di ottenere un sistema attivo a concentrazioni industriali. Le schiume sono state sottoposte a cicli di prove catalitiche a concentrazione di HMF crescente 0,02 M, 0,05 M e 0,10 M e caratterizzate prima e dopo la sequenza di prove con analisi SEM-EDS, XRD, spettroscopia raman. Le soluzioni sono state analizzate mediante ICP, GC-MS, ESI-MS. Con lo spostamento galvanico si ha la crescita di dendriti, formate prevalentemente sui bordi, e agglomerati di particelle nelle zone interne, mentre per elettrodeposizione si ottiene minore formazione di dendriti e particelle mediamente più piccole. La presenza di argento come fase attiva non migliora la conversione rispetto alle schiume monometalliche, ma causa un aumento di selettività ed efficienza faradica. Incrementando la concentrazione di HMF tutti i campioni presentano un aumento di conversione e un decremento di selettività ed efficienza faradica. Il catalizzatore ottenuto per spostamento galvanico, mostra prestazioni migliori a concentrazioni elevate e nelle prove di stabilità non dà segni di disattivazione, al contrario della schiuma preparata per elettrodeposizione che risulta leggermente disattivata.
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Mondello, Angelo. "Preparazione di elettrocatalizzatori 3D a base di Ag per la riduzione del 5-idrossimetilfurfurale." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15781/.
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Electrochemical reduction of the 5-hydroxymethylfurfural (HMF) - a biomass derived platform molecule to 2,5-bis (hydroxymethyl)furan (BHMF) - monomer for the manufacture of polyurethane foams or polyesters - is one promising alternative to the conventional hydrogenation since it is carried out at room temperature and using H+ or H2O as hydrogen suppliers, thus avoiding high pressure H2 source. In this work, we propose the use of Ag-supported copper open-cell foams to replace conventional 2D electrodes, which integrate the highly active performance of Ag nanoparticles with high geometrical surface area, mass and electron transfer of Cu open-cell foam creating a highly active 3D electrode for the reduction of HMF into BHMF.
The aim of the thesis is twofold: i) preparation of the Ag-supported Cu foam electrodes by galvanic displacement; ii) optimization of the electroreduction parameters. In the first part, the synthesis conditions are optimized based on three important parameters, namely the concentration of AgNO3, synthesis time, and stirring during the galvanic displacement as well as a combination with electrodeposition or multiple displacements. In the second part, the electrochemical reactions taking place are investigated (HMF and water reduction) to obtain not only high HMF conversion/BHMF selectivity but also high Faradaic efficiency. Moreover, a study about the effect of stirring rate (0 – 1000 rpm), HMF concentration (0.02 – 0.10 M), total charge transfer (up to 110 C), and electrode size (0.8 - 1.6 cm2) on the performances is carried out. The best catalyst exhibits a 99 % conversion of HMF with 99 % selectivity in BHMF and 93 % Faradaic efficiency in 0.02 M HMF. The catalyst is promising since it is quite stable after 9 cycle tests.
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Gupta, Saurabh. "Selective Catalytic Reduction (SCR) of nitric oxide with ammonia using Cu-ZSM-5 and Va-based honeycomb monolith catalysts effect of H2 pretreatment, NH3-to-NO ratio, O2, and space velocity /." Texas A&M University, 2003. http://hdl.handle.net/1969/526.
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Ross, Martin James. "Investigation into Catalytic Metallodrugs that Target Hepatitis C IRES RNA: Development, Characterization, and Mechanism." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1440421045.
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Berta, Holló. "Sinteza i karakterizacija nekih derivata pirazola i njihove reakcije sa prelaznim metalima." Phd thesis, Univerzitet u Novom Sadu, Prirodno-matematički fakultet u Novom Sadu, 2011. http://dx.doi.org/10.2298/NS20110922HOLLO.
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Reactions of 3,5-dimethylpyrazole-1-carboxamidinium nitrate (dpca∙HNO3) and 4-acetyl-3-amino-5-methylpyrazole (aamp) with transition metals under different reaction conditions are presented. The template reaction of aamp with triethyl orthoformate (teof) in the presence of metal ion is described. Besides, condensation of aamp with thiosemicarbazide (tsc) and the coordination of its product to copper(II) ion is also described. Twelve new complex compounds are synthesized and fully characterized. The characterization of two other, already known complexes is significantly enriched. The influence of HSAB interactions between the metal ions and ligators on the structures of obtained compounds is studied. The influence of the reaction conditions on the composition, structure and quality of crystals obtained in the reactions is investigated. Compounds are characterized by structural analysis, elemental analysis, molar conductivity data, infrared spectrometry and thermal analysis. Some selected complexes are characterized by UV-Vis spectra, magnetic measurements and biological activity tests, too.Reactions of 3,5-dimethylpyrazole-1-carboxamidinium nitrate (dpca∙HNO3) and 4-acetyl-3-amino-5-methylpyrazole (aamp) with transition metals under different reaction conditions are presented. The template reaction of aamp with triethyl orthoformate (teof) in the presence of metal ion is described. Besides, condensation of aamp with thiosemicarbazide (tsc) and the coordination of its product to copper(II) ion is also described. Twelve new complex compounds are synthesized and fully characterized. The characterization of two other, already known complexes is significantly enriched. The influence of HSAB interactions between the metal ions and ligators on the structures of obtained compounds is studied. The influence of the reaction conditions on the composition, structure and quality of crystals obtained in the reactions is investigated. Compounds are characterized by structural analysis, elemental analysis, molar conductivity data, infrared spectrometry and thermal analysis. Some selected complexes are characterized by UV-Vis spectra, magnetic measurements and biological activity tests, too
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Lolli, Alice. "Sintesi di catalizzatori supportati Au/Cu e studio della loro reattività per l'ossidazione selettiva del 5-idrossimetilfurfurale." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amslaurea.unibo.it/2549/.
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Al giorno d’oggi i combustibili fossili come carbone, olio e gas naturale forniscono più del 75% dell’energia mondiale. Tuttavia, la crescente richiesta di queste fonti di energia non rinnovabili, si manifesta in un momento in cui le riserve naturali si stanno esaurendo; è stato infatti stimato che le riserve petrolifere di tutto il mondo possano essere sufficienti per fornire energia e produrre prodotti chimici per i prossimi quarant’anni. Per questo motivo la conversione delle biomasse per produrre energia e prodotti chimici sta diventando una valida alternativa per diversificare le fonti energetiche e ridurre il surriscaldamento globale. Le biomasse, infatti, oltre ad essere una fonte rinnovabile, generano minori emissioni di gas serra rispetto ai combustibili fossili, perché la CO2 rilasciata nei processi di utilizzo viene bilanciata da quella consumata nel processo di crescita delle biomasse stesse.
Lo sfruttamento delle biomasse per la produzione di building blocks per la chimica suscita particolare interesse, poiché le molecole ottenute sono già parzialmente funzionalizzate; ciò significa che la sintesi di prodotti chimici specifici richiede un minor numero di stadi rispetto ai building blocks petroliferi, con conseguente diminuzione di prodotti di scarto e sottoprodotti.
Un esempio di queste potenziali “molecole piattaforma” è il 5-idrossimetilfurfurale (HMF), un importante composto derivato dalla disidratazione di zuccheri, intermedio chiave per la sintesi di un’ampia varietà di prodotti chimici e combustibili alternativi, tra cui l’acido 2,5- furandicarbossilico (FDCA), che è stato identificato tra i dodici composti chimici più importanti degli ultimi anni. Per esempio, il FDCA è un possibile sostituto dell’acido tereftalico, usato per produrre il polietilentereftalato (PET).
Recentemente alcuni autori hanno riportato interessanti risultati sull’ossidazione dell’HMF a FDCA utilizzando catalizzatori a base di Au supportato. Questi catalizzatori mostrano però significativi problemi di disattivazione.
Lo scopo di questo lavoro di tesi è stato quindi lo sviluppo di catalizzatori attivi e stabili nella reazione di ossidazione dell’HMF a FDCA.
Il lavoro portato avanti ha avuto come obbiettivi principali:
l’ottimizzazione della sintesi di nanoparticelle di oro e oro/rame a diverso rapporto molare, mediante un processo di sintesi, in acqua, a basso impatto ambientale. Tale metodo di sintesi si basa sull’azione riducente del sistema glucosio-NaOH ed è stato messo a punto in lavori di tesi precedenti. Le nanoparticelle sintetizzate sono state utilizzate, quali fase attiva, per la preparazione di catalizzatori supportati su TiO2 e CeO2
lo studio dell’attività catalitica e riusabilità dei catalizzatori preparati nell’ossidazione in fase liquida del HMF a FDCA.
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Lassoued, Abdessalem. "Caractérisation de catalyseurs solides par fluorescence induite par laser." Paris 6, 2001. http://www.theses.fr/2001PA066447.
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Hadjadj, Lakhdar. "Etude à la sonde atomique d'alliages à base titane." Rouen, 1988. http://www.theses.fr/1988ROUES014.
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Etude expérimentale dans les alliages Ti-3Cu, Ti-3Cu-5Al et Ti-10V-2Fe-3Al pour les alliages contenant du cuivre, analyse de la structure des zones de Guinier-Preston, et du rôle de l'aluminium sur la cinétique de précipitation en liaison avec le durcissement du matériau. Etude de l'évolution des phases oméga et alpha au cours des revenus pour l'alliage contenant du fer. Détermination à partir de cette étude, des structures des zones de Guinier-Preston et d'un mode de croissance pour la phase oméga. Analyse des avantages de la sonde atomique dus à sa haute résolution spatiale
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Martorell, Masip Benjamí. "Organic Molecules On Metal Surfaces: Forecasting Structures And Spectra." Doctoral thesis, Universitat Rovira i Virgili, 2008. http://hdl.handle.net/10803/9095.
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Chateigner, Daniel. "Etude de la texture cristallographique de céramiques et de couches minces supraconductrices YBa2Cu3O(7-delta) en relation avec les propriétés physiques." Université Joseph Fourier (Grenoble), 1994. http://www.theses.fr/1994GRE10149.
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Ce travail traite de l'analyse de la texture cristallographique de ceramiques et de couches minces du compose yba#2cu#3o#7-#, et de l'effet de cette texture sur les proprietes supraconductrices, principalement la densite de courant critique (jc). La diffraction des rayons x a ete surtout utilisee, completee pour certains echantillons par la diffraction des neutrons et la retrodiffusion des electrons. Dans le cas de l'utilisation des rayons x et de la geometrie de schulz par reflexion, les corrections de defocalisation indispensables a l'analyse quantitative des orientations preferentielles dans des couches minces et des multicouches ont ete developpees. Par ailleurs les conditions experimentales adaptees a l'etude d'echantillons tres textures, massifs ou minces ont ete precisees. Les echantillons massifs les plus textures ont ete elabores par des methodes derivees de la technique melt texture growth. En general, les echantillons textures en volume presentent deux orientations proches l'une de l'autre permettant d'expliquer les valeurs relativement faibles des densites de courant critique mesurees. La phase verte y#2bacuo#5 ne semble pas texturee dans les echantillons etudies. L'importance de la texture sur jc est clairement mise en evidence dans ce type d'echantillons, meme si l'etablissement d'une relation quantitative reste delicate. Pour les couches minces hetero-epitaxiees, l'utilisation d'un substrat monocristallin mgo oriente (001) entraine une interface tres perturbee pouvant expliquer les mauvaises proprietes supraconductrices des couches deposees (par rapport aux depots realises sur des substrats offrant un meilleur accord de maille avec ybco). La densite de courant critique est reliee quantitativement au degre de texture des films. De faibles pourcentages d'orientations secondaires diminuent jc de facon importante, inversement la presence de precipites de cuo peut avoir un effet benefique. Enfin l'analyse de la texture de dispositifs experimentaux a permis la caracterisation quantitative des orientations imposees artificiellement et necessaires a la creation de jonctions josephson
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Pal, Terek. "Unapređenje kvaliteta alata za livenje pod pritiskom primenom tehnologija inženjerstva površina." Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2016. http://www.cris.uns.ac.rs/record.jsf?recordId=101472&source=NDLTD&language=en.
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Proučavane su koroziona postojanost i tendencija lepljenja različitihmaterijala u kontaktu sa tečnom Al–Si–Cu legurom. Ispitivanjem suobuhvaćeni čelik za rad na toplo, plazma nitrirani čelik i dupleksslojevi sa CrN, TiAlN, TiAlSiN i CrAlN prevlakama, različitog nivoapovršinske hrapavosti. Za ispitivanja pomenutih fenomenaprimenjena je metoda izvlačenja, koja je unapređena kako bi se povećalenjena tačnost i verodostojnost simulacije procesa livenja. Korozioniefekti su pojačani tako što su uzorci osim kratkog kontakta sa odlivkomzadržavani i u dužim periodima u kontaktu sa tečnom legurom (5 i 20min). Uprkos opštim stavovima, za ispitivane materijale jeustanovljeno da su sile izvlačenja uzoraka iz Al–Si–Cu odlivakanezavisne od njihovog hemijskog sastava. Uticaj hrapavosti je izraženkod uzoraka sa prevlakama kod kojih pri smanjenju hrapavosti dolazi dopovećanja sile izvlačenja. Sve ispitane prevlake su sklone mehaničkomlepljenju Al–Si–Cu legure za svoje površine, ali sa aspekta korozije utečnom metalu značajno prevazilaze performanse čelika i plazmanitriranog sloja. Duži kontakt livene legure sa površinama prevlakauzrokovao je niže vrednosti sila izvlačenja, što je posledicaoksidacije površina prevlaka. Ustanovljeno je da su ispitivaneprevlake inertne ka tečnoj leguri aluminijuma. Međutim, dolazi dooksidacije i korozije materijala podloge kroz greške rasta koje suprisutne u prevlakama. Stečena znanja o identifikovanimmehanizmima habanja i propadanja zaštitnih slojeva prevlakaposlužiće daljem razvoju dupleks slojeva namenjenih za zaštitu alataza livenje pod pritiskom.Corrosion resistance and soldering tendency of different materials in moltenAl–Si–Cu alloy were studied. Hot-working tool steel, plasma nitrided steel andduplex layers with CrN, TiAlN, TiAlSiN and CrAlN top coatings, which wereproduced to various degree of surface roughness, were covered by the study.An ejection test was employed for investigation of the concerned phenomena.The ejection test was improved in order to increase its accuracy and thereliability of process simulation. Samples were examined in both short andextended periods of contact (5 and 20 min) with liquid casting. Castingsolidification was extended in order to intensify the corrosion effects. Contraryto common findings, it was found that the ejection force of the investigatedmaterials does not depend on their chemical composition. For the coatedsamples, a pronounced dependence of the ejection force on the surfaceroughness was found. The ejection force increases with decrease in surfaceroughness. All investigated coatings are prone to mechanical soldering by Al–Si–Cu alloy. Still, their corrosion resistance substantially exceeds the corrosionresistance of steel and plasma nitrided layer. Longer exposure of coatedsamples to cast alloy induced lower ejection forces, which is a consequenceof coatings oxidation. It was found that the investigated coatings are inert toliquid aluminium. However, the underlying material undergoes oxidation andcorrosion through coating growth defects. The findings concerning the wearmechanisms of protective layers support further development of duplex layersintended for die casting tools protection.
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Shen, Chia-Ching, and 沈家慶. "Study on 5-axis Tool Path Planning for Pencil-cut Machining." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/63358976162025325419.
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碩士國立臺北科技大學
機電整合研究所
101
The blending surface machining or so called pencil-cut machining between two curved surfaces is not easy, especially for complex or multi-surface components such as the blending surface of the impeller blade surface and hub surface. Usually, they must be cutting by using five-axis machine tool. In this paper, we proposed a tool path planning method for the blending surface pencil-cut machining. With this method, the pencil-cut (clean-up) machining tool path and the clean-up stages required can be generated by considering the allowable residual scallop material of the machined blending surface. For verification, the proposed method the parametric equations information of the intersecting curved surfaces to plan and calculate the tool paths for blending surface clean-up machining. By means of CAD/CAM software simulations and the actual machining experiments, the results show the present clean-up tool path planning method is actually feasible.
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Han, Sihui. "Le comportement d'hystérésis des solides et sa description par un schéma à mémoire discrète : le cas des aciers inoxydables." Habilitation à diriger des recherches, 1985. http://tel.archives-ouvertes.fr/tel-00319507.
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Étude du comportement d'un acier inoxydable 316L et d'un Inconel 718 dans le cadre d'un schéma thermomécanique à mémoire discrète constitué d'une équation multivoque, d'un critère d'inversion et d'un algorithme. Analyse détaillée des propriétés du comportement d'hystérésis pure. Etude des modules tangents aux courbes de charge. Mise en évidence de la restauration des propriétés du matériau après inversion et de la non-existence d'une discontinuité elastique-plastique dans le diagramme contrainte-déformation. Description de l'écrouissage en déformation à partir d'une analyse de la microstructure
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Kriegel, René. "Thermodynamische und elektrokatalytische Untersuchungen an zinkbasierten intermetallischen Verbindungen bei Raumtemperatur." 2017. https://monarch.qucosa.de/id/qucosa%3A21174.
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Die vorliegende Arbeit beschäftigt sich im ersten Teil mit einer Methodenentwicklung zur korrosionsfreien Ermittlung der elektromotorischen Kraft von zinkbasierten intermetallischen Verbindungen bei Raumtemperatur. Die durchgeführten Messungen bezüglich der elektrochemischen Potentiale von Verbindungen der binären intermetallischen Phasen Cu5Zn8, ZnPd und ZnPt mit jeweils verschiedenen elementaren Zusammensetzungen dienen als Basis zur Ermittlung der jeweiligen intrinsischen Aktivitäten der Einzelkomponente Zink. Messungen an der Referenzphase Cu5Zn8 wurden dabei zur Verifizierung der entwickelten Messmethodik durchgeführt. Die Untersuchungen an ZnPd- und ZnPt-Verbindungen liefern erstmalig thermodynamische Daten dieser Phasen bei Raumtemperatur.
Der zweite Teil dieser Arbeit beschäftigt sich mit der katalytischen Untersuchung von intermetallischen äquimolaren ZnPd-Elektroden hinsichtlich der elektrolytischen Wasserstoffentwicklung. Die durchgeführten Experimente legen den Schluss nahe, dass die katalytische Aktivität der intermetallischen Elektroden durch eine gezielte anodische Vorbehandlung signifikant gesteigert werden kann. Ex situ Charakterisierungen geben Grund zu der Annahme, dass die gesteigerte katalytische Aktivität durch die simultane Präsenz von oxidischer und metallischer beziehungsweise intermetallischer Spezies hervorgerufen wird.